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Standards for environmental performance in manufacturing

I was attending a manufacturing conference in Italy this last week and one of the major topics of discussion was green and sustainable manufacturing. There are a lot of other topics to be sure - but this one is building steam. The discussions range from process level issues, similar to the ones we've been discussing, to systems approaches, to design and, at one session, standards.

Not surprisingly, the standards associations (think ISO) have been busy and also, not surprisingly, the Europeans and Asian industry and some academics have been very busy as part of the standards process.

That light you see coming toward you in the tunnel is not the exit!

Let me elaborate.

The standards under development cover environmental and energy efficiency evaluation methods. Specifically, Professor F. Kimura of Hosei University in Japan outlined the work on ISO 20140 "Automation systems and integration – Environmental and energy efficiency evaluation method for manufacturing systems." According to Professor Kimura, who is participating in the standards development process, the environmental evaluation can focus on either a general environmental "intensity" at a rather high level for a facility or be more specific in nature.

I gather that the difference refers to whether or not a generic product being manufactured or system is evaluated. The system evaluation would apply to a comparison of improvements to a system, say by a change in the process or reconfiguration of a machine line or facility. Measurements might include energy per unit production, waste of materials, etc. For the evaluation of benefits or limitations to the production of a specific part or parts in factories located in different countries, there is provision of a general or specific evaluation of environmental intensity of products in manufacturing.

In the language of ISO,  this international standard establishes a method for evaluating environmental influences of manufacturing systems, e.g. energy/resource consumption and pollution.

The standard consists of five parts:
- ISO 20140-1:  Overview and general principles
- ISO 20140-2:  Guidelines for environmental evaluation procedures (this establishes procedures for environmental evaluation and will guide how to use parts 3 to 5)
- ISO 20140-3:  Environmental evaluation index model (this specifies the models for environmental indices, e.g. energy efficiency for manufacturing systems index)
- ISO 20140-4:  Environmental evaluation data model (this specifies data models for the environmental evaluation of manufacturing systems)
- ISO 20140-5:  Facility life cycle impact and indirect impact model (this specifies data models for a facility life cycle's direct and indirect impact on the environment)

To enable this environmental evaluation of manufacturing systems, various types of data from the manufacturing activity will be needed. Standards help to clearly define this data so that it can be used to perform unambiguous environmental evaluations. If there is generally accepted environmental intensity data for unit processes already available, that can also be used in the evaluation.

Much of the data related with manufacturing system definition and operation have been already standardized in related international standards. These existing standards will be included for use and, where necessary, extended.

Professor Kimura described some examples of the categories of likely required data:

- Manufacturing machine/facility (machine tools, conveyers, etc.),
- Tooling and jigs/fixtures,
- Energy,
- Materials,
- Product (definition, quality, function, etc.),
- Process plan,
- Production plan,
- Other production resources,
- Environmental evaluation data (intensity data, impact factors, etc.),

Based on these data, evaluation procedures of environmental index can be clearly defined. According to the definition of data format, it becomes possible for public organizations and machine/facility producers to publish their data. By relying on such published data in  standard formats, reliable and unambiguous environmental evaluation is realized. It also ties in with other existing standards.

For example, there are standards being developed on "Environmental evaluation of machine tools" (ISO/TC 39/WG 12). This is being developed by researchers at ETH (Swiss Federal Institute of Technology) in Zurich. They had a first meeting in May of this year and are working on an ISO series 14955 on this evaluation.

One can find a lot of information about this effort on the web by searching the technical committee (here ISO/TC39/WG12). One link to the Eco Machine Tools stakeholder meeting has several presentations on the elements of this standard.

Professor W. Knapp of ETH is leading this effort. He is a precision manufacturing engineering expert and very familiar with machine tools and their performance. They anticipate four areas of focus for this standard:

- ISO 14955-1, Eco-design methodology for machine tools

- ISO 14955-2, Methods of testing of energy consumption of machine tools and functional modules

- ISO 14955-3, Test pieces/test procedures and parameters for energy consumption on metal cutting machine tools

- ISO 14955-4, Test pieces/test procedures and parameters for energy consumption on metal forming machine tools

The functional modules will allow a certain degree of detail related to energy consumption, for example, the spindle, or drive axes, etc. It was noted that this will only address "use phase" energy - meaning, embedded energy due to raw material extraction, production of the machine or component, transports, set up and end of life energy requirements are ignored. For most of these machines the use phase is dominant.

One of the interesting aspects of these standards activities is the scope. This last standard mentioned will provide guidelines for designing machine tools to meet certain efficiency goals, and then indicate what kinds of parts (shape, complexity, processes needed) to evaluate how well the machine does! The earlier standard will set up a procedure and data requirements for doing comparisons. This will provide a basis of determining whether or not the suggested improvement, or relocation of a facility, will be beneficial environmentally.

One of the illustrations from a presentation made by the ETH folks as part of the TC 39/WG 12 discussion of the standard outlines the system boundaries for the analysis, see figure below. This

defines what inputs and outputs will come into play. Note, in the fine print below the figure, that raw parts in, new tools, etc. and output of machined parts, etc. are not considered if they don't represent a relevant energy flow (figure from Hagemann_Statusreport_ISO found on the stakeholder link above.)

A lot of the motivation for these standards comes out of the CECIMO organization in Europe. They describe themselves on their website as "CECIMO represents the common interests of the European Machine Tool Industries, particularly in relation to authorities and associations. CECIMO promotes the European Machine Tool Industry and its development in the fields of economy, technology and science."

Remember the early discussions about what motivates green manufacturing? I mentioned one was regional organizations - like CECIMO.  The industry is taking the initiative on this.

In the future, we will be designing and building machines and systems to meet these standards. And our factories producing products will be assessed using these standards.

Once again, the "Everett and Jones" philosophy (http://green-manufacturing.blogspot.com/2009/11/stylish-longevity.html) comes into play! Let's not be in the "what happened" category on this one.

I don't intend to. I'm going to follow this one closely and, as "unexciting' as standard development can be, this will be interesting!

We'll keep an eye on the standards activity and I will likely offer more details in the future.

A final point about technology and its impact on energy and the environment.

At another meeting I attended this summer, this one for the Machine Tool Technology Research Foundation (MTTRF) Dr. Masahiko Mori, President of Mori Seiki, gave an interesting presentation on where green product developments will likely impact manufacturing (and, by extension) green manufacturing. He cited some data from Nikkei Monodukuri on the number of parts in an engine for a conventional automobile versus a motor for an electric vehicle - 10,000 to 30,000 vs approximately 100, respectively!

This may seem like a simplistic comparison … but consider the complexity and impact of designing, manufacturing, storing or transporting and assembling 10,000 parts (not to mention the material issues and the building/floorspace requirements) compared to around 100.

This is an example of efficient resource utilization.

Of course there are the other bits needed to make the electric vehicle run - like a battery - but, overall, these are much simpler mechanical devices and will require fewer resources to build and, presumably, be easier to disassemble at end of life to recover the materials.

That's one way to do it!

Or, how to encourage conservation and save energy

A recent New York Times article discusses the draconian measures being taken by the Chinese government to make the nation more energy efficient ("China Fears Consumer Impact on Global Warming," K. Bradsher, NYT, July 4, 2010). In the last three years China has shut down more than a thousand older coal-fired plants and leads the rest of the world in investment on wind turbines and other clean technology according to the article. In addition, new, stringent, requirements for energy use and auto mileage are in place. But, the concern is that the growing demand of Chinese consumers will overwhelm even these efforts at green house gas (GHG) reduction. Apparently, this last winter and spring showed the largest six-month increase in GHG tonnage ever produced by a single country.

So, swing the ax at the low performers. That's one way to do it.

The NYT articles states that "China’s goal has been to reduce energy consumption per unit of economic output by 20 percent this year compared with 2005, and to reduce emissions of greenhouse gases per unit of economic output by 40 to 45 percent in 2020 compared with 2005."

Recall the "equation" for calculating impact first discussed in the September 1, 2009 posting? It states that:

Impact = Population x (GDP/person) x (Impact/GDP)  where GDP stands for gross domestic production

The challenge in China is that, in addition to population growth with time, the increasing standard of living is driving GDP/capita up and, as was noted in September 2009, unless you can reduce the Impact/GDP (that is, the role of manufacturing, energy generation and resource utilization) sufficiently, you will see the impact necessarily rise.

What is "sufficient"? Well, to close the gap between sustainable use of resources and the business as usual level (the chart that grows "up and to the right" for consumption and impact) you need to accomplish both a reduction in impact/GPP to track the required emissions and consumption trends but also reduce the impact/GDP to offset the growing demand of more and more consumers. It is sort of like trying to pay off a mortgage in an inflationary market when you are constantly taking out equity loans on top of the original mortgage. (Gee, we know how that works out!)

So, what to do? One approach is that used by China.

We are not likely to do that in the US. But, if you do business (or want to do business) in China your products may be affected by these regulations and decisions.

What about in the US? A recent Environmental Leader posting, July 15, 2010, on "Gov Contractors Must Track Emissions or Risk Losing Contracts" adds to the discussion. The article states "Contractors for the federal government that do not track their greenhouse gas (GHG) emissions could risk losing their contracts, according to a report in the Federal Times about new rules by the General Services Administration (GSA)."

It goes on to say that these rules result from the "GSA’s response to an executive order … issued in October which directed federal agencies to find ways to reduce their GHG emissions. Potentially, the new rules could have far-reaching consequences through the entire economy, not just government contractors."

Apparently, "only" scope 1 and 2 emissions reporting would be required, meaning emissions generated by employee commuting and business travel are not included. (We discussed emission scope reporting requirements in a prior posting.)

Given the large role of manufacturing industry serving as government contractors, this could have a big impact.

First, determine what impact your process has (at least energy to GHG conversion) and then roll out the green technology wedges!

So we may need to respond to consumer pressure or, more likely in the short term,  some form of regulation or standardization.

Some may call this taxes of some type. Or at least it has the effect of taxes to many. This is not too popular. I was reminded of Dan Rostenkowski, long time bull of the congress and head of House Ways and Means Committee, who died recently. He headed the committee that wrote most of the tax laws in the UA and he was famously quoted one time as saying "no one calls me up and asks me to raise their taxes!"

Cap and trade, or carbon trading, is often pointed to as one of the "taxes" that will impede industry (while promoting utilization of green technologies for manufacturing.) Another article on Environmental Leader's site calls that into question however. It is not simple. Apparently European Union (EU) companies are offsetting their emissions by improving the competitiveness of their competitors offshore through these carbon credit purchases (!) - so-called "leakage" - moving their business outside the EU. But, it doesn't appear to be increasing outsourcing of business overall according to other reports.

The article gives a neat site by Sandbag that shows a map illustrating the international trade in offsets between the EU and the rest of the world in 2009.

Programs like cap and trade, or regulation, or industry norms adopted to improve the impact of a specific industry all move us towards greener manufacturing. They occur because of competitiveness of countries and regions, real concerns about environment, customer demand, or just plain good economic or business sense.

Apropos that last comment about good business sense, I mentioned in a posting recently the comments of Jeff Immelt of GE on greening industry. He said that "with respect to companies like GE that want to stay ahead of the curve in terms of investing to maintain competitiveness and profitability,  … it’s going to change in like, 15 minutes one day.”  “I guarantee that’s going to happen.” He followed on commenting that since no one can predict when this will happen - you have to plan for this in your business strategy.

Regulation and industry norms take time. Breakthroughs in technology or process improvements can occur instantly. Be ready!

Degrees of Perfection, Part 4

Last of a 4 part series

We've been talking about exergy (or available energy and useful work) as part of this series. Last posting I reviewed the work of Professor Tim Gutowski of MIT on energy fundamentals in manufacturing. We'll continue along this line for this last in the series with an example from Professor Gutowski's work.

This series has generated some good comments and feedback. One pointed out a mistake in the previous posting (already corrected!) when I used the word "irreversibly" in place of reversibly - the correct word. This was in the quote from Gutowski's paper stating that exergy "represents the maximum amount of work that could be extracted from a system as it is reversibly brought equilibrium …" That is an important catch … sort of like using "nonpotable" for "potable." Thanks to that careful reader. More on some of the other comments below.

Now, on to an example.

Last time we spoke of a "typical" manufacturing system represented by a series of "boxes and arrows" connected serially and representing the individual processes and the connecting material transport between processes. We stated that we can replace (or augment) these arrows between boxes (or going into the box) with the systems mass, energy and entropy interactions. That means that each stage of a process can will have material flows or interactions as well as work and heat interactions. And there will be losses.

An earlier paper by Professor Gutowski used electrical energy in manufacturing from an energy perspective. The paper is titled "Electrical Energy Requirements for Manufacturing Processes and it was published in the Proceedings of the 13th CIRP Life Cycle Engineering Conference in 2006. You can find this publication on the web - it is number 23 under environmental publications.

In the last posting we talked about using exergy as a metric of performance. Gutowski tackles that in this paper.

Gutowski explains as a setup to the analysis that energy measures the potential of all materials to do work. "Fuels naturally have high values of exergy, but many other working materials, including pure metals, plastics and other organics, can have since we can then express these material and energy inputs and outputs in the same unit, usually joules (J).

He goes on. "Secondly, since the development of the concept of exergy is based upon the second law of thermodynamics, and not the first, it is not conserved. Hence this metric provides a measure of what is actually “used up” in the manufacturing process. As a result, a complex energy and material flow problem can be substantially simplified by using exergy analysis."

The process is broken up into two steps:
- 1) identify the system boundaries (that is the limits of the "box" we are analyzing, and
- 2) identify the exergy inputs and outputs.

Then, the difference between the inputs and the outputs is the exergy lost.

The paper explains that this "difference" can be used to "account for material transformations, including the conversion of raw working materials into products, wastes, and emissions, and the conversion of fuels (through combustion) into heat (to do work), wastes, and emissions." One can also extend the concept to incorporate all other energy sources, for example hydro, solar, electrochemical, and others.

Typically, we would consider the conversion of fuel (such as oil, coal or natural gas) to generate electricity which is then used in the manufacturing process for material conversion by, say, machining, grinding, welding, forming, forging, etc. As pointed out in an earlier posting on the variations of impacts depending on differing fuels for energy in different parts of the world, the exact fuel to energy relationship will vary.

The paper reminds us that to be fully consistent, we should take in to consideration the energy used to produce the materials we are "transforming" and, as this blog has argued, include the manufacture of the machinery to do the transforming as well.

The figure below, from Gutowski's paper, illustrates the energy and material inputs and outputs for a manufacturing process. This is a streamlined version of the input-output example discussed on the November 12th posting discussion whether or not lean is green and you can refer to that for additional background on "what's in the box." The example

followed in the paper deals with an automobile production machining line. As we've discussed in earlier postings, the machines used in these manufacturing lines have a number of elements and components that operate in parallel with the actual processing operation. For example, in the paper we are discussing, Gutowski mentions work handling, chip removal and treatment (removing oil) for recycling, tool changes, machine axis and spindle lubrication and temperature control, etc. in addition to actually machining the part. The figure representing this data for a typical automotive manufacturing machining line is below, from Gutowski, and shows the energy use breakdown as a function of vehicles produced.

So, as with our "tare heavy" and production "process heavy" discussion some postings ago) - this is an excellent example of tare heavy manufacturing. Here, a maximum of about 15% of the energy actually goes into machining the part. Granted, this is for a production line so there will be some expenditures of energy that might not be seen with a standalone machine tool. But, this is not very good.

One of the observations of the paper is that there is a variation with production rate. In fact, for standalone machine tools which may actually reach 60% or 70% energy usage for machining (and, thus, 40% or 30% for "all other") this maximum utilization varies with production rate as well. The takeaway is that, in production, there is a significant energy consumption for getting the machine ready for production and maintaining the machine (or line) readiness in the face of fluctuating production.

A more important observation from my perspective is that trying to estimate the energy consumption of manufacturing processes by looking only at the physical process (and the physics behind it - like metal cutting and the energy to form a chip, for example) will tell you almost nothing about the total energy consumption.

So what does this say about our "buy to fly ratio" analysis? To me, this is still a good way to characterize the efficiency of the process. In the example above (and under the assumptions detailed in the paper - the "academic fine print"!) we are utilizing at most 15% of the available energy coming into the process. That is, the transformation part of the manufacturing process is overwhelmed by the peripheral activities and requirements of the machine.

This is precisely what we were speaking about in our "low hanging fruit" discussion referenced above and what is motivating a lot of current development work by builders of and users of manufacturing machinery.

More on this to come.

Finally, one of the more prolific commenters to the blog talked about standardizing "by volume the process by which inputs, energy included, are transformed into outputs." A visual thinker! She goes on to say that with this approach "the perfect shape would be a cylinder, where all the outputs are useful, for nature, for humans or for both. The current processes are truncated cones with different "buy-to-fly" ratios symbolized by the ratio between the two bases. The cylinder's ratio is the perfect 1, no volume is lost."

The thought that came to mind when I read this was Rick Steves packing for a long trip on one of his adventures. He always seems to be wearing the same shirt and carries only a small backpack. How does he do that? If true, his "buy to fly" ratio must be close to cylindrical! That's perfection.

And, in the world of twitter - I learned of one called “50 Best Twitter Feeds To Stay On Top Of Green News”. The writer thought some of the blog readers might find it interesting. So, happy twittering!

Degrees of Perfection, Part 3

Part 3 of a series

Let's talk about exergy (or available energy and useful work).

With, again, apologies that Wikipedia is not a scholarly resource, the definition of exergy from Wikipedia goes like this: "the exergy of a system is the maximum useful work possible during a process." So, a measure of energy is a measure of our ability to achieve the most with what we have - sort of a thermodynamic "buy to fly" ratio!

The paper by Gutowski I referenced at the start of this series on July 2  gives an excellent discussion of the fundamentals of applying this to manufacturing. Gutowski explains that exergy "represents the maximum amount of work that could be extracted from a system as it is reversibly brought to equilibrium with a well-defined environmental reference state." This is usually comprised of physical energy (the portion of the system that can be removed from the system while bringing it's state to a "dead state" at a reference temperature and pressure, and chemical energy. Chemical energy refers to additional available energy potential by bringing the chemical potentials of a compound to equilibrium with its surroundings. Gutowski explains where these reference state data come from. And there are a lot of equations.

Ultimately, you can derive an expression that represents the work rate of a system derived from the explicit terms representing the physical and chemical exergy of the system.

To illustrate exergy flows, an excellent graphical image of the global energy flow, accumulation and destruction starting with sources of energy (solar primarily) to the eventual natural and anthropogenic destruction (that is, due to human activities, as opposed to that occurring in the biophysical environments without human influence) is presented by the Stanford Global Climate and Energy Project. The site also shows the global carbon flow and accumulation. Fascinating stuff.

Now comes applying this to manufacturing systems.

We defined some time ago the characteristics of a "typical" manufacturing system represented by a series of "boxes and arrows" connected serially and representing the individual processes and the connecting material transport between processes. (See the posting of November 12, 2009 for a refresher).

We can replace (or augment) these arrows between boxes (or going into the box as in the process box discussion in the posting referenced above) with the systems mass, energy and entropy interactions. Recall that entropy is a measure of "disorder" in a system and it increases over time. A typical example of entropy increasing is ice melting. This from the work of the person most credited with putting forth the idea of entropy, Rudolf Clausius in 1862. There is a change from solid, molecularly ordered ice, to "disordered" water as the water increases in temperature over time. Temperature is usually a conjugate variable of entropy in thermodynamics.

So, each stage of a process can have material flows or interactions as well as work and heat interactions. And, with each step and its associated interactions, there will be losses. These are the materials wasted (and accounting for the buy-to-fly ratio) as well as energy losses. Gutowski's paper goes into this analysis in great detail.

First we need to identify all of these "losses" so we can determine the system performance. Then, we can look at how the losses can be avoided, reduced, or "recovered" to improve the performance of the system.

That is, we then have another "metric" for manufacturing system design, operation and optimization.

More to come on this next time. But, I have some small items of (potential) interest to conclude with this time.

I don't "tweet" and don't follow those who do … but if I did … I would have been madly tweeting away the 13th of July from San Francisco. I was invited to a very splashy event hosted by General Electric touting the successes of their "ecomagination" initiative and announcing a new $200 million "Power Grid Challenge" to spur innovation and entrepreneurship in the electrical grid. The show included the GE Chairman and CEO Jeff Immelt, assorted venture capitalist who are helping with the program (like Emerald Technology Ventures, Foundation Capital, Kleiner Perkins Caufield & Byer, and RockPort Capital), Dr. Arun Majumdar, head of ARPA-E (DOE's advanced research agency for energy technology), the President of PG&E, our local utility, among others. One of two panels was chaired by the editor in chaired of Wired magazine and they have a short writeup on the funding part.

You can also check up on this at a GE website which gives the details and a link to the "challenge" website. The site includes a "tracker" listing the latest statistics on ideas submitted, comments and votes on ideas. They even have an app for an iPhone so you can track this on the road.

The comments of the panelists, including Mr. Immelt, were very interesting. Much was said about the potential for "low hanging fruit" - for example, the use of monitoring technology so the consumer can see their energy use (sometimes called "smart meters) is claimed to drive an immediate 10% reduction in consumption. If you see how much you are using, you use less of it! This relates to energy dashboards for manufacturing we've discussed.

Immelt's comments about the business aspects of conservation and sustainability were exceptionally noteworthy. There was a lot of discussion about the inevitability of the jump to eco-consciousness and clean energy. No one can tell when it will happen but it will. The Wired article referenced above quotes Immelt as saying, with respect to companies like GE that want to stay ahead of the curve in terms of investing to maintain competitiveness and profitability,  "…it’s going to change in like, 15 minutes one day.”  “I guarantee that’s going to happen.” He followed on commenting that since no one can predict when this will happen - you have to plan for this in your business strategy.

Wow! I felt like he was speaking to me (or maybe that he'd read the blog!)

To top it all off, during a Q&A session the inevitable question came up about all this potential regulation and conservation (specially pricing to encourage reducing consumption) and the impact it will have on business. Immelt stated "you can have a complete industrial base, and it can grow, while reducing green house gas" emission. This has been GE's experience based on information presented as part of their Ecomagination initative. Granted, this is not your small or medium enterprise but a Fortune 100 company (actually a Fortune 6 company!) But that really makes the case for getting on with it!

Finally, I was interviewed on a very interesting radio program the other day. The program, hosted by Colonel Mason, is called "The Promise of Tomorrow" and deals with the business of emerging science and nanotechnology. We spoke about green manufacturing for quite some time. You can listen to the broadcast at his website - it is program #114 broadcast on July 19th (see archives). He also mentions our upcoming book titled Green Manufacturing: Fundamentals and Applications  from Springer due out late this fall. More to come on this of course. It is already listed on Amazon if you want to "pre-order" a copy!

Degrees of Perfection, Part 2

Part 2 of a series

The degree of perfection discussion in the last posting was centered on the term "buy to fly" ratio popular in the aerospace industry to indicate material utilization. I stated that we need to consider all the peripheral "stuff" associated with a product like electronics, appliances, clothing, food, etc. which usually comes packaged so we might want to consider a sort of "buy to fly" ratio for conventional products.

I am aiming in this series to get to a more engineering discussion of exergy (or available energy and useful work) to address this. But, I want to play with this  more fascinating buy to fly concept for manufacturing a bit more.

In fact, based on a number of comments I've received on this, others also are intrigued by the extension of buy to fly to more general manufacturing applications and processes. Ralph Resnick, an old friend from my early days of chasing burrs, now at NCDMM, suggested something along the lines of "energy to manufacturing" for tracking the useful output of the process for the energy input. So, let's explore some other ways to implement this idea.

Last week I attended a research review conference held at a machine tool builder's product design and development facility in Northern California (DTL/Mori Seiki). We toured the facility and I noticed a machine, the Mori Seiki NT1000 mill turn center, that touted it's abilty to provide the same functionality in a 95 x 106 inch (or 2.4 x 2.7 meter) footprint that other machines requiring twice the size deliver. That is, more output per unit of floor space occupied. This measure is traditionally emphasized in the semiconductor industry where space in high tech clean rooms is very expensive.

You might recall that some time ago (last December to be exact), as part of a discussion about ways to green machines and processes I did a virtual comparison of a set of individual machines versus a multi-function machine. This NT1000 machine is one of those. So, in addition to the efficiencies of eliminating the other standalone machines, the reduction in floor space gives extra benefit that can be measured in terms of plant environment, lighting, construction costs and materials, etc.

But, let's push this a little further. The NT1000 and similar machines by other manufacturers has an approximate volume of 15.5 meters cubed and a work volume of approximately 0.06 meters cubed - a ratio of almost 260 to 1. I was curious how this compared to machine tools in general meaning - do we always need that big of a machine to make small parts? (The NT1000 is designed for precision machining for medical devices, automotive hardware, watches, instrumentation, etc.)

A few years back I had a visitor in my laboratory from Doshisha University in Japan. Professor Hirogaki was working on "downsizing" machine tools and presented some interesting data on what is "typical" in the machine tool industry - but he measured the relationship between the weight ratio (machine weight to removal weight) as a function of removal weight (or mass actually). The figure below, from Professor Hiragaki, shows some typical results (again you'll need to click on this for details).

Here, the "target" is a weight ratio of 1 which we approach as the machine size increases. So this would suggest that bigger machines are closer to "perfection."

Interestingly, if we plot the similar ratio for the multi-function machine we've been discussing, the data fits this graph nicely (down in the lower left of the x-axis). The machine mass is given as 8000 kg and the equivalent steel workpiece volume (removal volume) is about 470 kg for a ratio of machine mass to work volume mass of 17. But, and this is a big but, the multi-function machine replaces about 3 equivalently sized machine tools. So, by this "buy to fly" comparison - it looks quite good.

Others are working in micro-sized machines to make micro-sized parts to address this "why do we need a big machine for small parts?" issue. I was curious about how they match up. One leading company, Microlution sells a machine (the 363S CNC 3 axis horizontal mill) with a working volume 2x2x2 in (or 5x5x5 cm - roughly) in a machine volume of 24x24x54 in (or 61x61x137 cm). Volumetrically, this yields a ratio of machine volume to work volume of, gulp, almost 3900.  I did not do the mass ratio to see where this fits into Professor Hirogaki's curve.

Recall that the "conventional" multi-function machine tool above had a volume ratio of 260 to 1.

So, there are limits to using these type of calculations perhaps. Trying to make machines the size of the work volume (the "target" ratio of 1 in Hirogaki's figure) may not be feasible for small footprint machines. The trick is ... how to make larger parts with small features on the small machines?

Finally, lest we beat up on ourselves in the machining business too much, let's look again at microelectronics. In 2002, researchers Eric Williams and colleagues published a paper in Environmental Science and Technology on the "1.7kg microchip: energy and material use in the production of semiconductor devices" The chip, a 32MB DRAM chip with a mass of about 2 grams, requires a total weight of secondary fossil fuel and chemical inputs to produce it and use it  estimated to be 1600 g and 72 g, respectively. This is a buy to fly ratio coming of 835.  They also consider the use of water and elemental gases (mainly N2) in the fabrication stage which are 32000 and 700 g per chip, respectively. Using only those water and gas fabrication numbers gives us a buy to fly ratio of 8175 - a new high!

This points out the need for considering some additional ways to measure our "degree of perfection." That is the perfect transition to our discussion of exergy next time in part 3 of this series!

By the way, this posting is our one year anniversary of the blog. Happy Anniversary! We started this blog last July 15th and, thanks to your reading and feedback, it has been a great year. Thanks for following!

Degrees of Perfection

Part I of a series

Enough with the personal life analysis and reflections on sustainability - let's get back to techy stuff!

I know I said in the last posting that this time we'll look at how some industries are doing and guidelines/strategies they are using to move up on the "sustain-o-meter." Well, let's start this process by another type of  self examination - dealing with the "degree of perfection" for manufacturing.

This discussion is going to take a few postings so we'll do this as a series starting, today, with one way to look at performance and some examples.

This term "degree of perfection" comes, originally, from a 1988 book by Jan Szargut and colleagues (Exergy Analysis of Thermal Chemical and Metallurgical Processes, Springer-Verlag, New York, 1988 - Amazon has it!). We'll get to exergy later. But, first, perfection!

The term "degree of perfection" is a ratio of useful products to inputs. The most recent discussion I read that referred to this was a paper by a clever person I've referred to before, Tim Gutowski at MIT, and others, in Env. Sci. Technology on "Thermodynamic Analysis of Resources used in Manufacturing Processes."

This term is used in a variety of ways and sort of represents a manufacturing "bang for the buck" measure. But before we delve into the thermodynamic aspects of this, let's look at conventional measures.

One of the more novel uses is in the aerospace industry where it is called "buy to fly ratio." Boeing, for example,  has a long history of tracking this value. Due to the peculiar requirements of aircraft components (demanding precision, unique shapes, incredible strength and fatigue requirements, etc.) many structural components (from wing spars to ribs) and many other parts, like landing gear, are machined out of large blocks of material. This results in most of the material going to waste. Buy to fly ratios in the 30's are common. This means, only a bit over 3% of the material purchased actually ends up on the plane. This waste for machined components is usually in the form of chips - which are recycled of course but discarded never-the-less.

In fact, some postings ago I referred to the role of precision in sustainable manufacturing under the topic of "Little things matter". I stated that if the machining process used in aircraft production is under control and precision manufacturing principles applied, a reduction in machining tolerances from +/- 0.006 inches to +/- 0.004 inches on the features of the airframe can account for a weight reduction of 10,000 pounds/aircraft and substantial fuel savings (8%). This allows an increase of 10% in passengers (engines don't need to carry as much plane), and substantial reduction in manufacturing cost of the aircraft (less material and improved assembly). That reduces the need for the original material (one can spec the rough material tighter if the machining tolerances are better controlled) but that will only reduce the waste slightly.

Recent trends in material costs, production time (even if you throw the chips  away you have to machine them in the first place) and performance have allowed aerospace companies to focus on this more. Switching to other materials, like high strength titanium, allows reduced part size with similar strength or other performance.

Switching to other production methods (beside machining away most of the material) such as laser welding of complex rib components can make huge savings. Using laser welding to produce a rib component that had previously been machined resulted in a reduction in the buy-to-fly ratio from 30:1 to 3:1 (see article).

Ditto for use of carbon fibers. But in this case, the concern is how to better reuse the fibers or replace processes that generate so much scrap. A recent article in Plastics Today discusses Boeing's recent efforts to find secondary outlets for carbon fibers reclaimed from aircraft production. The article states "For its purposes, Boeing is buying the highest grades of carbon fibers available: AS4, IM7, T8005, which can cost anywhere from $5-$50/lb as virgin materials. Of the amount it buys however, much of it ends up as scrap ... the buy-to-fly ratio for materials is less than 33%, meaning that 2/3 end up as production waste."

And to make matters worse, the fibers are usually encased in an epoxy matrix which requires processing to remove them.

So, what would you do if you were paying $50/pound for raw materials and then threw away 2/3's in your manufacturing process? Just so we don't forget that this is an not easy task, recall that a typical Boeing 737 has about 367,000 parts and even an average car as about 15,000 parts. So, we are not talking about toothpick production here.

And, we need to consider all the peripheral "stuff" associated with a product. Planes are delivered "au natural" if you will. But electronics, appliances, clothing, food, etc. is usually packaged (and sometimes several times for transport to distribution centers before it gets to the shelf) and that is part of the "buy to fly" ratio for conventional products.

Point made on the need to measure and track degree of perfection and manufacturing performance!

But, the original concept of degree of perfection does not speak specifically to material use ratios but useful output in terms of energy compared to input energy. The term used is exergy - a term you should have heard if you went to engineering school and took a thermodynamics course and may remember or - if you had a good physics course in high school.

Next time we will dive deeper into exergy and the concept of available energy and useful work. This forms an interesting basis for measuring the performance of manufacturing processes and material conversion/transformation and could allow us to look at the potential for greening and process improvement in a new way. This could be a better way to evaluate alternate technology.

Individually green

The "sustain-o-meter" discussion last posting got a number of good comments and got me thinking about how this might apply to individuals and their living habits.

Actually, to be fair, I was sort of thinking about this but then saw an article on GreenBiz.com by Joel Makover posted on June 17th titled "Who's the Biggest Greenwasher of Them All?" The article discusses the statements of major corporations indicating their commitment and accomplishments in creating green business and the degree of skepticism that we often associate with these statements. The article asks, basically, if this level of scrutiny was applied to consumers (yep, you and me) would we be able to show that we've stepped up to the plate and made significant changes in commitment or documented accomplishments towards "greening" our lives.

After all, the products these companies manufacture and sell are bought by someone. Are consumers stepping up in choosing to embrace sustainability and green behavior?

Gulp. Apparently not.

Mr. Makover refers to "anonymous polls and surveys in which high percentages of consumers make boastful claims -- saying they regularly seek out green products, recycle and compost at home, are more energy conscious in their purchasing decisions, switch brands in favor of greener ones, take public transportation whenever possible, invest their money with so-called responsible funds and companies, and otherwise take action on behalf of the planet."

But, truth be known, the reality is different. Mr. Makover states that "Shoppers overwhelmingly buy what they want, most likely the same things they've always bought, perhaps with an exception or two. Except during brief periods of high fuel prices, they drive what they've always driven with little regard for alternatives. Despite 20 years of green consumer surveys suggesting otherwise, people haven't changed their shopping habits much."

And I've heard anecdotal evidence to support this regarding the tremendous differences noted when surveying consumers on their purchase preferences on entering a major "big box" retailer and then reviewing what they actually bought on exit.

Mr. Makover does also balance these comments with companies who have shown clear evidence of greenwashing in the past - so he levels the complaint equally. But, he says "If consumers were a corporation, we'd be boycotting them."

(Note: If you are interested in more on the topic of greenwashing, the posting of last July 30th covered some definitions and links to sites for reviewing examples from advertising.)

But back to the "sustain-o-meter." Although this was designed with a "corporate" context in mind, it can apply to individuals. For example, you can do a global search and replace for:

- "customers" to be replaced with "vendors" as in "engaging supply chain and vendors"
- "implement" to be replaced with "purchase or install" as in "define and purchase or install" tech wedges for more challenging problems"
- "manufacturing" to be replaced with "purchasing" as in "proactive sustainable purchasing," and
- "design" to be replaced with "living" as in "proactive living for sustainability"

and add this to the meter and this gives some better rating bases for individuals.

I have to honestly say that I'd place myself at the mid-point of the scale - somewhere between "defining solution wedges for low hanging fruit" and "define and install." Meaning, I've done things like:  changed all the incandescent bulbs to compact flourescent, installed a digital thermostat for changing the heating periods in my house (and shutting of the furnace at night), and installed a very efficient gas furnace (no chimney ... just blows out water vapor through a PVC tube!).

Oh, yes, and my brother got me a "kill-a-watt" meter for my birthday last year so I can see what my appliances are doing. That's "measuring and tracking performance."

But, you can also check on what your appliances are up to at a neat-o GE website for "Visualizing your gadgets' energy thirst."  Did you know 1 kWh of electricity will make 36 pieces of toast in a toaster but 100 pieces in a toaster oven? Or print 1,333 pages on a printer? You could spend hours checking things out on this site. But, be careful - you only get 7 hours of computer monitor use for a kilowatt!

Where would you rate yourself on the "sustain-o-meter"?

Next time we'll look at how some industries are doing and guidelines/strategies they are using to move up on the "sustain-o-meter."